Los Angeles, CA

Crenshaw/LAX Transit Corridor Project

Client: Los Angeles County Metropolitan Transportation Authority (Metro)
Our Role: Engineering Services

Los Angeles County Metropolitan Transportation Authority (Metro) and other stakeholders looked to construct a new metro line to spur economic growth and enhance mobility in South Los Angeles and connect the area with Los Angeles International Airport (LAX).

The Crenshaw/LAX Transit Corridor Project offers an alternative transportation option to congested roadways and provides significant environmental and transit equity benefits to the South Los Angeles community.

Previously known as the Crenshaw/LAX Line, the K Line extends from the E Line at Expo/Crenshaw Station and merges with the C Line at Aviation/LAX Station to connect the Crenshaw Corridor, Inglewood, and El Segundo.

The line’s new stations include Expo/Crenshaw, Martin Luther King, Jr., Leimert Park, Hyde Park, Fairview Heights, Downtown Inglewood, Westchester/Veterans, and Aviation/Century.

GFT provided temporary support of excavation (SOE) engineering design and independent design review services to the Walsh/Shea Corridor Constructors Joint Venture (WSCC) for the project.

Our team designed temporary excavation support systems up to 38 feet deep and 7,000 feet long for the cut-and-cover construction of guideways for new underground rail stations being installed as part of Metro’s transit corridor expansion. The SOE system was designed with integral traffic decking spanning the top of select portions of Crenshaw Boulevard, conveying public traffic over the excavation and supporting existing operational utilities in place.

The excavation support system featured steel soldier piles internally braced with pipe struts across a 45- to 55-foot-wide trench. The system incorporated both cantilevered and full-width steel beams supporting concrete decking to allow excavation and construction of the guideways while maintaining traffic on Crenshaw Boulevard. The soil between the soldier piles was retained by timber lagging. Pipe struts were preloaded with hydraulic rams and then welded in place to minimize shoring deflections during excavation.

We worked closely with WSCC to optimize and customize design details. Variable strut sizes, alternative member shapes and configurations, and varying layouts were considered to accommodate the use of specialized construction equipment and procedures and complex staging requirements. Additionally, we coordinated extensively with Metro and the Los Angeles Bureau of Engineering, as well as the project’s geotechnical engineering and underground guideway design teams, to ensure successful project completion while meeting stringent Metro design criteria.

Key Features

Steel soldier piles and timber lagging provide safe, time-tested excavation support.
Preloaded internal pipe strut configuration supports excavation walls with minimum deflections and allows for the use of specialized guideway construction equipment with high-clearance requirements.
Integral concrete decking and a maintenance of traffic plan minimized travel disruptions in this key city artery.

Outcomes

- New access to opportunity for numerous South Los Angeles communities, including Crenshaw Corridor, Hyde Park, Leimert Park, Fairview Heights, Inglewood, and Westchester.
- Easier access to medical facilities, workplaces, and commerce centers throughout Los Angeles.
- Key connection of K Line of Downtown Los Angeles with LAX coming in 2024.
public engagement.
Provides long-term flexibility to accommodate evolving content and technology.